The present disclosure relates generally to measuring mechanical fatigue in downhole loading cables and, more particularly, to determining mechanical fatigue in polymer composite material based wireline or slickline cables using thermally-induced acoustic waves.
Hydrocarbons, such as oil and gas, are commonly obtained from subterranean formations that may be located onshore or offshore. When performing operations for removing the hydrocarbons from the subterranean formations, it may be desirable to obtain information about the formation. One method of obtaining information about the formation is the use of a wellbore logging tool coupled to a wireline or slickline system, wherein the wellbore logging tool is lowered into the wellbore using a downhole loading cable. Mechanical fatigue of the polymer composite material based cable may occur over time due to structural defects in the cable (e.g., small cracks, delaminations, or voids) and may cause logging service failure during logging operations. Current nondestructive cable inspection methods (e.g., x-ray, microwave, or gamma-ray inspection methods) may require a direct measurement of a portion of the logging tool cable, and may therefore require the cable to be relatively stationary while the measurement is taken. However, the logging tool cable may be lowered into the well during logging operations at high velocities, making stationary methods of measuring mechanical fatigue on the cable impracticable. It is therefore desirable to provide a dynamic and nondestructive inspection method to identify potential cable failure events, onset of failure modes in the cable, and degradation trends in the cable's structural strength.
While embodiments of this disclosure have been depicted and described and are defined by reference to example embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.